1. Field of the Invention
The present invention relates to an electronic component including a laminated capacitor, and a substrate-type terminal having the laminated capacitor mounted thereon and mounted on a circuit board.
2. Description of the Related Art
Currently, chip components, and small laminated capacitors in particular, are frequently used on a circuit board of a mobile terminal such as a mobile telephone having an increasingly reduced thickness. A laminated capacitor includes a ceramic laminated body in a rectangular parallelepiped shape serving as a capacitor and including internal electrodes, and external electrodes formed on opposite end surfaces of the ceramic laminated body opposite to each other in a longitudinal direction thereof.
Generally, the laminated capacitor is electrically and physically connected to a circuit board by placing the external electrodes directly on mounting lands of the circuit board, and joining the mounting lands and the external electrodes with a joining material such as solder.
In such a laminated capacitor, small mechanical distortion occurs upon application of voltage. When this distortion is transmitted to the circuit board, audible sound, or as is commonly referred to as acoustic noise, may occur in the circuit board. To address this issue, the laminated capacitor is sometimes mounted on the circuit board with a substrate-type terminal interposed therebetween (see e.g., Japanese Patent Laying-Open No. 2004-134430 or Japanese Patent Laying-Open No. 2012-204572).
The substrate-type terminal is a substrate including an upper electrode joined to the external electrodes of the laminated capacitor, a lower electrode joined to the mounting lands of the circuit board, and a connection conductor connecting the upper and lower electrodes together.
In the configuration disclosed in Japanese Patent Laying-Open No. 2004-134430, a lower electrode and an upper electrode on an interposer substrate serving as the substrate-type terminal are arranged in directions intersecting with each other. As such, external electrodes on a laminated capacitor and mounted electrodes on a circuit board are arranged in directions intersecting with each other, resulting in difficulty in transmitting the distortion in the laminated capacitor to the circuit board. By adopting this configuration, therefore, the occurrence of acoustic noise in the circuit board can be suppressed.
A land pattern of a circuit board required to mount an interposer substrate having such a configuration on the circuit board is different in shape than a land pattern of a circuit board required to mount a laminated capacitor without an interposer substrate on the circuit board. This means that the land pattern needs to be altered, which is difficult to achieve in current circuit boards of which high-density mounting is required. Accordingly, the use of an interposer substrate having the above configuration results in difficulty in reducing the sizes of the circuit board and the like, thus contributing to increased costs.
In the configuration disclosed in Japanese Patent Laying-Open No. 2012-204572, an interposer substrate is provided with grooves extending to positions overlapping with the laminated capacitor when viewed in a direction perpendicular to an upper surface of the laminated capacitor. Thus, even if a lower electrode and an upper electrode on the interposer substrate are arranged in the same direction, the occurrence of acoustic noise in the circuit board can be suppressed. This configuration is also applicable to current circuit boards of which high-density mounting is required, without the need to alter the land pattern as described above.
However, since the recent increase in capacity of the laminated capacitor tends to increase the distortion in the laminated capacitor, the occurrence of acoustic noise in the circuit board is not sufficiently suppressed even if this configuration is adopted.